Method for assembling a magnetic head assembly and magnetic disk drive using bonding balls connecting magnetic head terminals to wiring terminals

ABSTRACT

A method for assembling a magnetic head assembly with a slider and a magnetic head including forming, on a slider supporting member, a terminal connected to a magnetic head terminal. In addition, the method includes fixing a head slider on the slider supporting member so that the head terminal faces the terminal of the slider supporting member and contacting a conductive ball member to both of the head terminal and the terminal of the slider supporting member. Furthermore, the method includes pressing the ball member to bond the head terminal with the terminal of the slider supporting member so that the ball member connects the terminals electrically and mechanically.

CROSS REFERENCE TO THE RELATED PRIORITY APPLICATIONS

This application is a Continuation-In-Part application of both U.S.application Ser. No. 08/774,554 filed Dec. 30, 1996 and U.S. applicationSer. No. 08/896,435 filed Jul. 18, 1997 now U.S. Pat. No. 6,002,550.U.S. application Ser. No. 08/896,435 is a divisional application of U.S.application Ser. No. 08/030,365 filed Mar. 17, 1993, which is nowabandoned in favor of an FWC application Ser. No. 08/896,729 filed Jul.18, 1997 now U.S. Pat. No. 6,141,182. Application 08/774,554 is itself aContinuation-In-Part of both U.S. application Ser. No. 08/613,601 filedMar. 11, 1996 and U.S. application Ser. No. 08/248,334 filed May 24,1994 now U.S. Pat. No. 5,612,840. U.S. application Ser. No. 08/613,601is an FWC of U.S. application Ser. No. 08/110,771 filed Aug. 23, 1993,now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a magnetic head assembly having athin-film or MR type magnetic head used for a magnetic disk drive.

2. Description of the Related Art

Recently, in conventional magnetic disk drives, monolithic type magneticheads have been replaced with thin-film or MR type magnetic heads.

FIG. 1A is an exploded view of an example of a magnetic head assembly(which can also be referred to as a magnetic head suspension unit)having a thin-film type magnetic head used for the conventional magneticdisk drives. FIG. 1B is an exploded view of a part of the magnetic headsuspension unit shown in FIG. 1A. In the present specification, themagnetic head suspension unit refers to an assembly of a spring armhaving a magnetic head mounted on an end of the spring arm. The otherend of the spring arm is adapted to be mounted on a member of a magnetichead positioning mechanism.

Referring now to FIG. 1A, one end (a base portion 1 a) of a spring arm(suspension) 1 formed of an elastic plate is mounted to a member of amagnetic head positioning mechanism (not shown in the figure) via aplate-like spacer 2. A gimbal 3 is mounted on another end 1 b of thespring arm 1. The gimbal 3 is mounted, as shown in FIG. 1B, on thespring arm 1 by means of laser welding at positions indicated by x. Acore slider (head slider) 4 of a magnetic head h is mounted by adhesiveon the gimbal 3.

Two magnetic head elements 5 are formed on a rear side surface of themagnetic head, the magnetic head elements 5 being connected by leadwires 6 which lead to a read wire 8 covered with an insulating tube 7fixed to the spring arm 1. The lead wire 8 is lead to arecording/reproducing circuit 9 shown in FIG. 2.

The spring arm 1 is slightly bent near the base portion 1 a so that abent portion 1 c is formed so as to generate a spring force.

FIG. 2 is an exploded view of a conventional magnetic disk drive inwhich two magnetic head suspension units shown in FIG. 1A are used.

Two magnetic head suspension units are mounted on a driving arm 13 whichpivots about an axis 12 so that a magnetic disk 10 accommodated insidethe magnetic head drive is sandwiched between two of the core sliders 4mounted on the respective spring arms 1. Each of the core sliders 4 ispressed to a respective surface of the magnetic disk 10 by the springforce generated by the bent portion 1 c.

When the magnetic disk 10 is rotated at a high speed, the magnetic headsh float, if the magnetic heads h are of the floating type, on therespective surface of the magnetic disk 10 due to an air flow generatedby the rotation of the magnetic disk 10. If the magnetic heads h arecontact type magnetic heads, the magnetic heads h do not float, butinstead slide on the respective surfaces of the magnetic disk 10. Themagnetic heads h are moved to respective target tracks on the surfacesof the magnetic disk 10 by pivoting the spring arms about the axis 12.

FIG. 3 is a perspective view of a thin-film type magnetic head. FIG. 4is an enlarged cross sectional view of the thin-film type magnetic headshown in FIG. 3 taken along a line A—A of FIG. 3.

The thin-film type magnetic head shown in FIG. 3 comprises the slider 4and head elements 5. The head elements 5 are formed by means of a filmdeposition technique and lithography. Terminals 15 a and 15 b forrecording/reproducing coils are provided near the head elements 5.

Each of the head elements 5 comprises a lower magnetic pole 16, an uppermagnetic pole 17 and a thin-film coil 19 wound around a connectingportion 18 between the lower magnetic pole 16 and the upper magneticpole 17. A gap insulating layer 20 is provided between the lowermagnetic pole 16 and the upper magnetic pole 17 so that a gap G having apredetermined width is formed between the two poles. The gap G faces thesurface of the magnetic disk 10 to perform an magneticrecording/reproducing operation.

In the construction of the magnetic head suspension unit shown in FIG. 1in which the lead wire 8 is covered with the insulating tube 7, theinsulating tube 7 occupies a relatively large space to preventminiaturization of the magnetic disk drive. Additionally, the insulatingtube 7 makes an assembling operation difficult, particularly anautomated assembling operation. Further, there is a strong possibilitythat the lead wire 8 will pick up noises, resulting in degradation of anS/N ratio of a signal sent via the lead wire 8.

In order to eliminate the above-mentioned problems, a method for forminga signal transmitting line on a spring arm is suggested in JapaneseLaid-Open Patent Application No.4-21918. In the method, a signal line isformed of a pattern of a conductive layer on an insulating layer formedon the spring arm. However, the method has a problem in that the signaltransmitting line formed of the conductive layer is easily damaged orbroken during a process for forming the bent portion 1 c shown in FIG.1A.

Japanese Laid-Open Patent Application No.4-111217 discloses a magnetichead suspension unit in which a flexible printed circuit board isattached to a spring arm, and a portion of the flexible circuit boardcorresponding to the above of the spring arm bent portion is not adheredto the spring arm. Instead, in this construction, the portion of theflexible printed circuit board corresponding to the bent portion of thespring arm is free, and thus there is no bending stress applied to theflexible printed circuit board. However, this construction cannot beapplied to a highly miniaturized spring arm such as a spring arm havinga thickness of a few microns and a 4.6 mm width.

There is another problem in that ability of the insulating layers 21 and22 of the magnetic head element 5 to withstand dielectric voltage isvery low because they each have a thickness of only 1 to a few microns.Accordingly, if a relatively high voltage of about 100V or more isapplied between the thin-film coil 19 and the poles 16 and 17 due to ageneration of static electricity, the insulating layers 21 and 22 may beeasily damaged due to electric discharge.

If the insulation between the thin-film coil 19 and the poles 16 or 17is damaged, an electric discharge may occur between the core slider,which is made of a conductive material such as Al₂O₃TiC, and themagnetic poles 16 or 17, resulting in the gap G or the floating surfaceof the core slider 4 being damaged. Additionally, when the magnetic diskdrive is in operation, an electric discharge may occur between themagnetic disk 10 and the magnetic poles 16 or 17, resulting in themagnetic gap G being damaged. When the core slider 4 is damaged, thefloating characteristic of the magnetic head is deteriorated, whichcondition causes a generation of noises in the recording/reproducingsignal. If the magnetic head is a contact type head, the damaged surfaceof the magnetic head may scratch the magnetic disk 10.

Problems similar to the above-mentioned problems may occur when the coreslider is miniaturized. That is, when the magnetic head is heated, themagnetic head tends to expand due to the thermal expansion, but aportion of the core slider attached to the gimbal or the spring arm byadhesive cannot expand in accordance with the expansion of the magnetichead. This creates bending of the core slider, and thus the floatingcharacteristic of the magnetic head may be deteriorated.

SUMMARY OF THE INVENTION

It is a general object of the present invention to provide an improvedand useful magnetic head assembly and a magnetic disk drive having sucha magnetic head suspension unit in which the above-mentioneddisadvantages are eliminated.

A more specific object of the present invention is to provide a magnetichead assembly and a magnetic disk drive in which damaging of aconductive-pattern layer formed on a spring arm during a process ofbending the spring arm can be prevented.

Another object of the present invention is to provide a magnetic headassembly and a magnetic disk drive in which no insulation breakageoccurs due to generation of static electricity.

Another object of the present invention is to provide a magnetic headassembly and a magnetic disk drive in which thermal deformation of aslider core is prevented.

In order to achieve the above-mentioned objects, there is providedaccording to the present invention, a magnetic head assembly comprising:

a slider on which a magnetic head is mounted, the slider havingterminals of the magnetic head;

a gimbal portion on which the slider is mounted;

terminals of wiring lines; and

balls bonding the terminals of the wiring lines and the terminals of theslider.

The magnetic head assembly may be configured so that the balls are madeof gold.

The magnetic head assembly may be configured so that the terminals ofthe wiring lines are provided on the gimbal portion.

The magnetic head assembly may be configured so that the wiring linesare formed by a wiring pattern.

The magnetic head assembly may be configured so that the slider isprovided on a surface of the gimbal portion on which the wiring linesare provided.

The magnetic head assembly may be configured so that the slider isprovided on the gimbal portion so that the terminals of the wiringpattern and the terminals of the slider face each other in an orthogonalformation.

The magnetic head assembly may be configured so that the gimbal portionis a part of a suspension so that the gimbal portion is integrallyformed with the suspension.

The magnetic head assembly may be configured so that the wiring linesare formed by a wiring pattern formed on the suspension.

The magnetic head assembly may be configured so that the slider isprovided on a surface of the gimbal portion on which the wiring linesare provided.

The magnetic head assembly may be configured so that the slider isprovided on the gimbal portion so that the terminals of the wiringpattern and the terminals of the slider face each other in an orthogonalformation.

The above objects of the present invention are also achieved by amagnetic disk drive comprising:

an enclosure;

a magnetic disk provided in the enclosure;

a magnetic head assembly provided in the enclosure; and

an actuator to which the magnetic head suspension unit is fixed, theactuator moving the magnetic head assembly above the magnetic disk,wherein the magnetic head assembly is configured as described above.

BRIEF DESCRIPTION OF THE DRAWINGS

The other objects, features and advantages of the present invention willbe apparent from the following detailed description when read inconjunction with the accompanying drawings, in which:

FIG. 1A is an exploded view of an example of a magnetic head assemblyhaving the thin-film type magnetic head used for the conventionalmagnetic disk drives;

FIG. 1B is an exploded view of a part of the magnetic head assemblyshown in FIG. 1A;

FIG. 2 is an exploded view of a conventional magnetic disk drive inwhich two magnetic head assemblies shown in FIG. 1A are used;

FIG. 3 is a perspective view of a thin-film type magnetic head;

FIG. 4 is an enlarged cross sectional view of the thin-film typemagnetic head shown in FIG. 3 taken along a line 4—4 of FIG. 3;

FIG. 5A is a perspective view of a first embodiment of a magnetic headassembly according to the present invention;

FIG. 5B is an enlarged cross sectional view taken along a line b—b ofFIG. 5A;

FIG. 6A is a perspective view of the spring arm shown in FIG. 5A in astate where a magnetic head has not been mounted on a gimbal;

FIG. 6B is an illustration showing a process for formingconductive-pattern layers on the spring arm;

FIGS. 7A through 7C are illustrations showing a process for bending thebent portions shown in FIG. 6A;

FIG. 8A is a perspective view of a second embodiment of a magnetic headassembly according to the present invention;

FIG. 8B is an enlarged partial cross sectional view taken along a lineb—b of FIG. 8A;

FIG. 8C is an enlarged partial cross sectional view taken along a linec—c of FIG. 8A;

FIG. 8D is a partial cross sectional view of a variation of the springarm shown in FIG. 8A;

FIG. 9A is a perspective view of a third embodiment of a magnetic headassembly according to the present invention;

FIG. 9B is a cross sectional view taken along a line B—B of FIG. 9A;

FIG. 10 is a perspective view of a fourth embodiment of a magnetic headassembly according to the present invention;

FIG. 11A is a perspective view of a fifth embodiment of a magnetic headassembly according to the present invention;

FIG. 11B is an enlarged partial cross sectional view taken along a lineB—B of FIG. 11A.

FIG. 12A is a perspective view of a sixth embodiment of a magnetic headassembly according to the preset invention;

FIG. 12B is an enlarged partial cross sectional view taken along a lineb—b of FIG. 12A;

FIG. 12C is an enlarged partial cross sectional view taken along a lineC—C of FIG. 12A;

FIG. 13A is a perspective view of a seventh embodiment of a magnetichead assembly according to the present invention;

FIG. 13B is a variation of the embodiment shown in FIG. 13A;

FIG. 14 is a perspective view of an eighth embodiment of a magnetic headassembly according to the present invention;

FIG. 15A is a perspective view of the magnetic head shown in FIG. 14;

FIG. 15B is a cross sectional view taken along a line B—B of FIG. 15A;

FIG. 16 is an exploded view of an essential part of a ninth embodimentof a magnetic head assembly according to the present invention;

FIG. 17 is an exploded view of an essential part of a variation of theninth embodiment shown in FIG. 16;

FIG. 18 is a perspective view of an essential part of a tenth embodimentof a magnetic head assembly according to the present invention;

FIG. 19 is an exploded view of an eleventh embodiment of a magnetic headassembly according to the present invention;

FIG. 20A is a perspective view of a spring arm of a twelfth embodimentof a magnetic head assembly according to the present invention;

FIG. 20B is an enlarged cross sectional view of a mounting structure ofthe core slider shown in FIG. 20A;

FIGS. 21A through 21F are illustrations of variations of the hole shownin FIG. 20A; and

FIG. 22A is a perspective view of a spring arm of a thirteenthembodiment of a magnetic head assembly according to the presentinvention;

FIG. 22B is an enlarged cross sectional view of a mounting structure ofthe core slider shown in FIG. 22A;

FIG. 22C is an enlarged cross sectional view showing a variation of themounting structure shown in FIG. 22B;

FIG. 23 is a perspective view of a magnetic head assembly according to afourteenth embodiment of the present invention;

FIG. 24 is a plan view of a 3.5-inch magnetic disk drive to which themagnetic head assembly shown in FIG. 23 is applied;

FIG. 25 is a perspective view of a first-order bend state of asuspension shown in FIG. 23;

FIG. 26 is a perspective view of a first-order twist state of thesuspension shown in FIG. 23;

FIG. 27 is a perspective view of the upper side of the magnetic headassembly shown in FIG. 23;

FIG. 28 is a side view of the magnetic head assembly shown in FIG. 23;

FIG. 29 is a perspective view of a magnetic head assembly according to afifteenth embodiment of the present invention;

FIG. 30 is a perspective view of a magnetic head assembly according to asixteenth embodiment of the present invention;

FIG. 31 is a perspective view of a magnetic head assembly according tothe twelfth embodiment of the present invention;

FIG. 32 is a side view of the mechanism shown in FIG. 31;

FIG. 33 is a perspective view of a magnetic head assembly according toan eighteenth embodiment of the present invention;

FIG. 34 is a perspective view of a magnetic head assembly according to anineteenth embodiment of the present invention;

FIG. 35 is a plan view of a free-end part of a suspension shown in FIG.34;

FIG. 36 is a sectional-view taken along a line XIV—XIV shown in FIG. 34;

FIG. 37 is a perspective view of a magnetic head slider shown in FIG.34;

FIG. 38 is a flowchart of a production process for the suspension shownin FIG. 34;

FIG. 39 is a plan view of a plate obtained after an etching step shownin FIG. 38 is carried out;

FIG. 40 is a flowchart of another production process for the suspensionshown in FIG. 34;

FIG. 41 is a perspective view of a variation of the nineteenthembodiment of the present invention;

FIG. 42 is a perspective view of a magnetic head assembly according to atwelfth embodiment of the present invention;

FIG. 43 is a plan view of a magnetic disk drive to which the magnetichead assembly shown in FIG. 42 is applied;

FIGS. 44A and 44B are respectively plan and side views of the magnetichead assembly shown in FIG. 42;

FIG. 45 is a side view of a state observed when the magnetic headassembly shown in FIG. 42 is provided in the magnetic disk drive;

FIG. 46 is an emphasized view of the state in FIG. 45;

FIG. 47 is a side view of a first-order bend state of a suspension usedin the twelfth embodiment of the present invention;

FIG. 48 is a side view of a first-order twist state of the suspensionused in the twelfth embodiment of the present invention;

FIG. 49 is a plan view of a first variation of a gimbal of thesuspension used in the twelfth embodiment of the present invention;

FIG. 50 is a plan view of a second variation of the gimbal of thesuspension used in the twelfth embodiment of the present invention;

FIG. 51 is a plan view of a third variation of the gimbal of thesuspension used in the twelfth embodiment of the present invention;

FIG. 52 is a plan view of a fourth variation of the gimbal of thesuspension used in the twelfth embodiment of the present invention;

FIG. 53 is a plan view of a fifth variation of the gimbal of thesuspension used in the twelfth embodiment of the present invention; and

FIG. 54 is a side view of a variation of the twelfth embodiment of thepresent invention.

FIG. 55 is a top view of another embodiment of a magnetic disk apparatusof the present invention;

FIG. 56 is a cross section of the magnetic disk apparatus in FIG. 55;

FIG. 57 is a top view of an actuator in FIG. 55;

FIG. 58 is a perspective view of a magnetic head assembly according to afurther embodiment of the present invention;

FIG. 59 illustrates another connecting mechanism of the magnetic headassembly in FIG. 58;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description will now be given, with reference to FIGS. 5A and 5B, of afirst embodiment of the present invention. FIG. 5A is a perspective viewof a first embodiment of a magnetic head assembly according to thepresent invention, and FIG. 5B is an enlarged cross sectional view takenalong a line B—B of FIG. 5A. Hereinafter, the magnetic head assembly isalso referred to a magnetic head suspension unit or merely suspensionunit. In FIGS. 5A and 5B, parts that are the same as the parts shown inFIG. 1A are given the same reference numerals, and descriptions thereofwill be omitted.

The first embodiment according to the present invention comprises thespring arm 1 and the core slider 4 of the magnetic head. A gimbal 24supported by bridge portions 23 a and 23 b is formed on the end 1 b ofthe spring arm 1. The core slider (head slider) 4 of the magnetic headis mounted on the gimbal 24 by an adhesive which has an insulationeffect and can be an insulation adhesive or an adhesive containing aninsulator. The insulation adhesive is an insulator in which theinsulator itself has the insulation effect.

The base portion (attachment portion) 1 a of the spring arm 1 is fixedto a member of a magnetic head positioning mechanism. Conductive-patternlayers 25 run from the base portion la to the gimbal 24 so as totransmit signals to/from the magnetic head.

FIG. 6A is a perspective view of the spring arm 1 shown in FIG. 5A in astate where the magnetic head has not been mounted on the gimbal 24. InFIG. 6A, a portion of the core slider 4 is also shown to explainelectrical connection between the magnetic head and theconductive-pattern layers 25. A pad 25 a is formed at the end of each ofthe two conductive-pattern layers 25. The core slider of the magnetichead is also provided with pads 26. When the core slider 4 is mounted onthe gimbal 24, the pads 26 make contact with the respective pads 25 a.The pads 26 and the pads 25 a are then soldered together to assure anelectric connection. It should be noted that the core slider 4 in FIG.6A is viewed from a direction indicated by an arrow B of FIG. 5A.

The conductive-pattern layers 25 on the spring arm 1 are formed by aprocess shown in FIG. 6B. As shown by FIG. 6B-2, an insulating layer 27is formed on the spring arm 1 by applying a polyimide resin over thespring arm 1 made of stainless steel. The thickness of the spring arm 1is about 25 μm, and the thickness of the insulating layer 27 is 3-4 μm.A base layer 28 is then formed on the insulating layer 27, as shown inFIG. 6B-3, by sputtering copper (Cu) onto the insulating layer 27. Thebase layer 28 may instead be formed by vapor deposition or chemicalplating.

Using the base layer 28, electro plating is performed to form a copperlayer 29 on the base layer 28, as shown in FIG. 6B-4. As shown in FIG.6B-5, the base layer 28 and the copper layer 29 are etched so that theconductive-pattern layers 25 remain on the spring arm 1. Lastly,polyimide resin is applied over the conductive-pattern layers 25 so asto form an insulating film 30 which covers the conductive-pattern layers25 to protect them.

If a bending process is performed by applying a pressing force to theconductive-pattern layers 25 formed on the spring arm 1, theconductive-pattern layers 25 may be damaged or destroyed. In order toeliminate this problem, in the first embodiment of the presentinvention, rectangular holes 31 a and 31 b are formed on the spring arm1, as shown in FIG. 5A, on either side of the conductive-pattern layers25. The rectangular holes 31 a and 31 b separate a portion of the springarm 1, on which the conductive-pattern layers 25 are formed, from bentportions 33 a and 33 b to which a pressing force is applied to bend thespring arm 1. The rectangular holes 31 a and 31 b may instead be slits32 a and 32 b as shown in FIG. 6A.

FIGS. 7A through 7C are illustrations showing a process for bending thebent portions 33 a and 33 b. As shown in FIG. 7A, first a roller 34having larger diameter portions 35 a and 35 b is prepared. The largerdiameter portions 35 a and 35 b bends the corresponding bent portions 33a and 33 b. The bent portions 33 a and 33 b, which are formed as anelastic portion R generating an elastic force, of spring arm 1 areplaced on a rubber table 36. The roller 34 is then rolled, as shown inFIG. 7B, on the bent portion 33 a and 33 b while it is being pressed. Asa result, only the bent portions 33 a and 33 b are permanently deformedinto an arc-like shape, while the portion of the spring arm 1, on whichportion the conductive-pattern layers are formed, between the bentportions 33 a and 33 b is elastically deformed.

According to the present embodiment, the roller 34 is not pressed on theportion where the conductive-pattern layers 25 have been formed, andthus no damage to the conductive-pattern layers 25 occurs.

A description will now be given, with reference to FIGS. 8A through 8D,of a second embodiment according to the present invention. FIG. 8A is aperspective view of a second embodiment of a magnetic head suspensionunit according to the present invention; FIG. 8B is an enlarged partialcross sectional view taken along a line b—b of FIG. 8A; FIG. 8C is anenlarged partial cross sectional view taken along a line c—c of FIG. 8A.FIG. 8D is a partial cross sectional view of a variation of the springarm shown in FIG. 8A.

In the present embodiment, a recessed portion 39 is formed in theelastic portion R where an elastic force is generated. Theconductive-pattern layers 25 are formed in the recessed portion 39. Therecessed portion 39 covers an entire length C of the elastic portion Rand a width B so as to cover the portions of the conductive-patternlayers 25 located in the elastic portion R of the spring arm 1.

In this embodiment, a portion of the insulating layer 27 shown in FIG.6B-2 is formed also inside the recessed portion 39. The base layer 28and the copper layer 29 are then formed on the entire surface of theinsulating layer 27 including the portion thereof inside the recessedportion 39 so as to form the conductive-pattern layers 25. Lastly, theinsulating layer 30 is formed on the conductive-pattern layers 25 sothat a top surface of the insulating layer 30 located inside therecessed portion 39 is below the surface of the spring arm 1 as shown inFIG. 8B.

In the present invention, since the portion inside the recessed portion39 do not come into contact with the roller for forming the bentportions even though the roller has a straight cylindrical surface, nodamage occurs to the conductive-pattern layers 25, the same as in thecase of the above-mentioned first embodiment.

Although in the above embodiment the recessed portion 39 is formed bymeans of etching, the recessed portion 39 may instead be formed by meansof press forming as shown in FIG. 8D. By using press forming, therecessed portion 39 can be formed even if the thickness of the springarm 1 is very slight or the total thickness of the insulating layers 27and 30 and the conductive-pattern layers 25 is great. The recessedportion 39 may be formed so that an entire length 25L of straightportions of the conductive-pattern layers 25 is embedded in the recessedportion 39.

A description will now be given, with reference to FIGS. 9A and 9B, of athird embodiment according to the present invention. FIG. 9A is aperspective view of a third embodiment of a magnetic head suspensionunit according to the present invention; FIG. 9B is a cross sectionalview taken along a line b—b of FIG. 9A.

In the present embodiment, portions 25 r of the conductive-patternlayers 25, corresponding to the elastic portion R which generates anelastic force, are wider than other portions of the conductive-patternlayers 25. That is, a width C₁ of each of the portion 25 r of theconductive-pattern layers 25 within the elastic portion R is widenedover a length L corresponding to the elastic portion R. The totalthickness of the conductive-pattern layers 25 and insulating layers 27and 30 is uniform over the entire width of the widened portions 25 r ofthe conductive-pattern layers 25. A roller 35 having a straightcylindrical surface is pressed over the entire width of the elasticportion R so as to bend the elastic portion R.

If the conductive-pattern layers 25 or the insulating layer 30 in theelastic portion R are protruded as shown in FIG. 6B, the pressing forceexerted by the roller 35 is concentrated onto the conductive-patternlayers 25. However, in the present embodiment, the pressing force isdispersed onto the entire width of the widened conductive-pattern layers25, and thus damage or breakage of the conductive-pattern layers 25 isprevented. Additionally, even if damage such as a cracking of portionsof the conductive-pattern layers 25 occurs, other portions of the layers25 which are not damaged, resulting in reliable electric continuity. Inthe present embodiment, the width c1 of each of the portion 25 r of theconductive-pattern layers 25 is 2.0 mm, and the length L is 1.5 mm.

A description will now be given, with reference to FIG. 10, of a fourthembodiment according to the present invention. FIG. 10 is a perspectiveview of a fourth embodiment of a magnetic head suspension unit accordingto the present invention.

In the present embodiment, zigzagging conductive-pattern portions 25 zof the conductive-pattern layers 25 within the elastic portion R areformed to extend in a direction oblique to a direction in which otherportions of the conductive-pattern layers 25 extend. Preferably, U-turnportions 25 c are formed with a width greater than other portions. As aresult, in the present embodiment, pressing force is dispersed over thecontacting area of the roller to be pressed, thus reducing damaging andbreakage of the conductive-pattern layers 25.

A description will now be given, with reference to FIGS. 11A and 11B, ofa fifth embodiment of the present invention. FIG. 11A is a perspectiveview of a fourth embodiment of a magnetic head suspension unit accordingto the present invention; FIG. 11B is an enlarged partial crosssectional view taken along a line b—b of FIG. 11A.

In the present embodiment, a plurality of dummy patterns 25 d are formedwithin the elastic portion R. The dummy patterns 25 d have the sameconstruction as the conductive-pattern layers 25. When the elasticportion R is pressed by the roller 35 as shown in FIG. 11B, the pressingforce is dispersed onto the dummy patterns 25 d, and thus damage andbreakage of the conductive-pattern layers 25 is prevented unlike in thecase of the conventional conductive-pattern layers in which the pressingforce is concentrated onto the conductive-pattern layers.

FIG. 12A is a perspective view of a sixth embodiment of a magnetic headsuspension unit according to the preset invention; FIG. 12B is anenlarged partial cross sectional view taken along a line b—b of FIG.12A; FIG. 12C is an enlarged partial cross sectional view taken along aline C—C of FIG. 12A. In the sixth embodiment, a protecting layer isformed over portions of the conductive-pattern layers 25 in the elasticportion R. The protecting layer comprises a conducting layer 37 and aninsulating layer 38.

In order to make the present embodiment, a copper base layer is formedon the insulating layer 30 in the process shown in FIG. 6B-3-6. Theconductive layer 37 made of copper is then formed by means of electroplating, and the layer 37 is patterned. Polyimide resin is coated overthe conductive layer 37 so as to form the insulating layer 38.Preferably, the insulating layer 30 formed over the conductive-patternlayers 25 is formed with a relatively great thickness so that theinsulating layer 30 can be flattened and smoothed by means of surfacepolishing. The conductive layer 37 has a relatively large width B tocover the conductive-pattern layers 25, and has a length C which coversthe length of the elastic portion R as shown in FIG. 12A.

In the present embodiment, the roller 35 exerts a pressing force ontothe conductive layer 37 which has a relatively high strength, and thusthe pressing force is uniformly dispersed onto the conductive layer 37.Accordingly, damage to the conductive-pattern layers 25 is preventedwhen the spring arm 1 is bent by the roller 35.

FIG. 13A is a perspective view of a seventh embodiment of a magnetichead suspension unit according to the present invention. In the seventhembodiment, extra conductive-pattern layers 25 s are formed. The extraconductive-pattern layers 25 s are formed along each of the conductivelayers 25. Both ends of each of the additional conductive-pattern layers25 s are connected to the ends of the respective conductive-patternlayers 25 at corresponding connection parts 40 and 41. Accordingly, ifone of the conductive-pattern layers 25 is damaged to lose continuity,the corresponding extra conductive-pattern layer 25 s serves the samefunction as the damaged conductive-pattern layer 25. Therefore, areliable connection can be realized.

FIG. 13B is a variation of the seventh embodiment according to thepresent invention. In this variation, each of the conductive-patternlayers 25 has two paths along the straight portion thereof within theelastic portion R. One of the paths serves as the extraconductive-pattern layer 25 s.

In all the above-mentioned embodiments and variations thereof, althoughthe bent portions are formed by a press method using a roller, othermethod using a mold press or laser may be used.

Since the spring arm 1 according to the above-mentioned embodiments ismounted on a member of the magnetic head positioning mechanism, as shownin FIG. 2, the magnetic disk drive can reliably transmitrecording/reproducing signals through the spring arm.

A description will now be given, with reference to FIG. 14 and FIGS. 15Aand 15B, of an eighth embodiment according to the present invention.FIG. 14 is a perspective view of the eighth embodiment of a magnetichead suspension unit according to the present invention. In FIG. 14,parts that are the same as the parts shown in FIG. 1A are given the samereference numerals, and descriptions thereof will be omitted. FIG. 15Ais a perspective view of the magnetic head h shown in FIG. 14; FIG. 15Bis a cross sectional view taken along a line b—b of FIG. 15A.

In the eighth embodiment according to the present invention, the coreslider 4 is mounted on the gimbal 3 by adhesive 42 having a highinsulating effect. The core slider 4 may instead be directly mounted onthe end 1 b of the spring arm 1. Although, in the prior art, the coreslider is also mounted by adhesive having an insulating effect, theelectric resistance between the core slider 4 and the gimbal 3 is lowbecause the adhesive layer is very thin. Accordingly, the core slider 4may be at the same potential, that is a ground potential, as the springarm 1 because the spring arm 1 is grounded. If a high voltage staticelectricity is generated in the thin-film coil of the magnetic headelement 5, the insulating layer between the thin-film coil and themagnetic pole is damaged, resulting in electric discharge between thethin-film coil and the core slider.

In the eighth embodiment, in order to obtain a high resistance betweenthe core slider and the gimbal 3, a thick layer of the adhesive 42 isprovided. It is preferable that the adhesive 42 be a UV cure resin(ultra-violet cure type adhesive). Alternatively, epoxy resin may beused. In the present embodiment, as shown in FIG. 15A, the adhesive 42comprises an insulating material powder 42 b mixed in adhesive medium 42a. Accordingly, the adhesive 42 can have a high electric resistance, andis formed with a relatively great thickness, and thus the insulationbetween the core slider 4 and the gimbal 3 is improved.

FIG. 16 is an exploded view of an essential part of a ninth embodimentof a magnetic head suspension unit according to the present invention.In the ninth embodiment, the core slider 4 is mounted on the gimbal 3 orthe end 1 b of the spring arm 1 via an insulator 43. In the presentembodiment, the insulator 43 is formed by applying insulating resin suchas a photoresist onto a surface of the core slider 4. The core slider ismounted on the gimbal 3 by applying adhesive 44 onto the insulator 43.Alternatively, as shown in FIG. 17, the insulator 43 may be applied ontoa mounting surface of the gimbal 3.

FIG. 18 is a perspective view of an essential part of a tenth embodimentaccording to the present invention. In FIG. 18, a magnetic headcomprising the magnetic head elements 5 and a core slider 4 i is shown.Unlike the conventional magnetic head, the core slider 4 i is made of aninsulating material such as SiO₂. Accordingly, the discharge asdescribed in relation to the conventional magnetic head can beeliminated.

FIG. 19 is an exploded view of an eleventh embodiment of a magnetic headsuspension unit according to the present invention. I the presentembodiment, the magnetic head suspension unit is mounted on a drivingarm 13 of the magnetic head driving mechanism via an insulating member45. The insulating member has screw holes 46 into which screws forfastening the magnetic head suspension unit to the driving arm 13 areinserted. The screws are made of synthetic resin or metal screws coveredwith synthetic resin. Accordingly, the spring arm 1 is insulated fromthe driving arm 13, which may be grounded. Alternatively, the spacer 2may be made of an insulating material.

In the present embodiment, since the spring arm is not electricallyconnected to the driving arm 13, which may be grounded, no electricdischarge occurs between the core slider 4 and the magnetic pole.

FIG. 20A is a perspective view of a spring arm of a twelfth embodimentof a magnetic head suspension unit according to the present invention;FIG. 20B is an enlarged cross sectional view showing a mountingstructure of the core slider shown in FIG. 20A. In the presentembodiment, a gimbal 24 formed on the spring arm 1 has a hole 47 in thecenter thereof. As shown in FIG. 20B, the core slider 4 is mounted onthe gimbal 24 by adhesive 48 so that the hole 47 is filled with theadhesive 48. Since the hole is formed in the gimbal 24, the gimbal canbe easily bent, if bending stress is applied to the gimbal 24 due to adifference in thermal expansion between the core slider and the gimbal24. Accordingly, bending stress applied to the core slider 4 is reducedsince the gimbal 24 is bent instead of the core slider 4. This featureis important when a thin and miniaturized core slider is used.

Variations of the hole 47 are shown in FIGS. 21A through 21F. Aplurality of holes 47 may be provided, and each hole may have arectangular shape.

In the present embodiment, the hole 47 is filled with a part of theadhesive applied between the core slider 4 and the gimbal 24, so thatthe strength of the adhesion between the core slider 4 and the gimbal 24is increased. Additionally, if the UV cure resin is used, anultra-violet beam can be irradiated through the hole 47, whicheffectively cures the UV cure resin, and thus the strength of the curedUV cure resin can be improved.

It should be noted that although the gimbal 24 is integrally formed withthe spring arm 1, the gimbal 24 may be formed separately from the springarm 1; that is, it may be fixed to the spring arm 1 by means of weldingdescribed in regard to the conventional magnetic head suspension unitshown in FIG. 1B.

FIG. 22A is a perspective view of a spring arm of a thirteenthembodiment of a magnetic head suspension unit according to the presentinvention; FIG. 22B is an enlarged cross sectional view of a mountingstructure of the core slider shown in FIG. 22A; FIG. 22C is an enlargedcross sectional view showing a variation of the mounting structure shownin FIG. 22B. In the present embodiment, an opening 49 is provided in thegimbal 24, into which opening the core slider is inserted. The opening49 is slightly larger than the outer dimension of the core slider 4.

The core slider 4 is mounted in a state where side faces of the slidercore 4 is fixed, as shown in FIG. 22B, by adhesive 50 to the outer edgeof the opening 49. Alternatively, as shown in FIG. 22C, the core slider4 may be formed to have a step in its side surface so that dimension L₂is larger than dimension L₁. The dimension of the opening is determinedto be a value between L₁ and L₂. The adhesive such as UV cure resin isapplied to the outer edge of the opening after the core slider 4 isinserted into the opening 49. An ultra-violet beam is, then irradiatedfrom a direction indicated by an arrow in FIG. 22C so as to cure the UVcure resin.

In the present embodiment, since the core slider 4 is supported at theside surfaces thereof, stress generated by thermal expansion of thegimbal 24 is lessened. Accordingly, deformation of the core slider 4 dueto the thermal expansion of the gimbal can be efficiently prevented.

It should be noted that the magnetic heads shown in FIGS. 20A and 22Aare formed with an MR element formed by means of thin-film technology.Thin-film type magnetic head elements are formed on the MR element.However, the present invention is not limited to the specific magnetichead, and a conventional thin-film type magnetic head or a monolithictype magnetic head may be used.

A description will now be given, with reference to FIG. 23, of amagnetic head suspension unit 120 according to a fourteenth embodimentof the present invention.

FIG. 24 shows a 3.5-inch type magnetic disk drive 1220 to which themagnetic head suspension unit 120 is applied. The magnetic disk drive1220 has an enclosure 1221 in which a 3.5-inch magnetic disk 1222, ahead positioning actuator 1223 and other parts are housed.

A suspension (load beam) 121 made of stainless steel is fixed to an arm122 of the actuator 223. The suspension 121 has a curved bent portion123 generating elasticity. In this regard, the curved portion 123 of thesuspension 121 is also referred to as an elastic portion 123 in thefollowing description. The suspension 121 has a stiffness portion 24extending from the elastic portion 123, and ribs 121 a. The elasticportion 123 provides a magnetic head slider (core slider) 135 with aload in a direction in which the magnetic head slider 135 moves andcomes into contact with a magnetic disk 1222. The suspension 121 has auniform thickness of, for example, approximately 25 μm, which is equalto one-third of the thickness of a suspension of a 3380-type (IBM) headsuspension unit.

It is desirable that the width W1 of the suspension 121 is made as smallas possible, desirably 4 mm or less. This is because the resonancefrequency of vibration of the suspension 121 is prevented from lowering.

A gimbal 125 is integrally formed in the suspension 121 so that thesuspension 121 and the gimbal has a one-piece construction which uses aplate. The gimbal 125 includes a pair of C-shaped openings 126 and 126facing each other in the longitudinal direction of the suspension 121.Two slits 128 and 129 are formed in the suspension 121 along respectivesides of the suspension 121.

The gimbal 125 includes a magnetic slider fixing portion 130, a firstpair of beam portions 131 and 132, and a second pair of beam portions133 and 134. The magnetic head slider fixing portion 130 has largesurface dimensions enough to fix the magnetic head slider 135 thereon,and has the same dimensions as the magnetic head slider 135 (a=1.6 mm,b=2.0 mm). However, it is possible for the slider fixing portion 130 tohave an area less than the magnetic head slider 135 when a sufficientadhesive strength can be obtained.

The magnetic head slider 135 is a light weight structure type slider,which has been proposed in Japanese Patent Laid-Open Application No.4-228157. The proposed slider has a flat back surface opposite to a diskfacing surface. The flat back surface of the slider is fixed to thefixing portion 130 by means of an adhesive, which can be an insulationadhesive or an adhesive including an insulator (for example, insulatorpower). In this case, the slider 135 is located so that the centerthereof corresponds to the center of the fixing portion 130. It is alsopossible to use other types of sliders.

The beam portions 131 and 132 extend outwardly from the respective sidesof the fixing portion 130 along a line (suspension width direction line)138, which passes through the center of the fixing portion 130 (theabove center is also the center of the slider 135), and crosses alongitudinal center line 137 of the suspension 121 at a right angle.Each of the beam portions 131 and 132 has a length 1 ₁.

The beam portion 133 extends from the beam portion 131 towards therespective sides of the beam portion 131 so that the beam portion 133crosses the beam portion 131 at a right angle and extends parallel tothe line 137. Similarly, the beam portion 134 extends from the beamportion 132 towards the respective sides of the beam portion 132 so thatthe beam portion 134 crosses the beam portion 132 at a right angle andextends in parallel with the line 137. The beam portion 133 is joined toportions 140 and 141 of the suspension 121 in the periphery of thegimbal 125. Similarly, the beam portion 134 is joined to portions 142and 143 of the suspension 121 in the periphery of the gimbal 125. Inother words, the beam portion 133 extends from the portions 140 and 141of the gimbal 125, and the beam portion 134 extends from the portions142 and 143 of the gimbal 125. The distance between the center of thebeam portion 133 and one of the two ends thereof is 1₂. Similarly, thedistance between the center of the beam portion 134 and one of the twoends thereof is also 1₂.

The beam portion 133 and the beam portion 131 form a T-shaped beam 139A.Similarly, the beam portion 134 and the beam portion 132 form a T-shapedbeam 139B. The beam portions 131, 132, 133 and 134 form an H-shapedbeam. It will be noted that the fixing portion 130, the first pair ofbeams 131 and 132, and the second pair of beams 133 and 134 are portionsof the suspension 121.

The length l₁ of the first pair of beams 131 and 132 is limited by thewidth W1 of the suspension 121. As the width W1 of the suspension 121 isincreased, the resonance frequency of a bend and twist of the suspension121 becomes lower, and the flying characteristics of the slider 135 aredegraded. For these reasons, the width W1 cannot be increased. However,according to the fourteenth embodiment of the present invention, it ispossible to increase the length l₂ of the second pair of beams 133 and134 without being limited by the width W1 of the suspension 121. Thesecond pair of beams 133 and 134 is formed so that l₂>l₁. That is, eachof the T-shaped beams 39A and 39B has a leg portion and an arm portionlonger than the leg portion.

When a waviness of the magnetic disk being rotated is present or dustadheres to the magnetic disk, the magnetic head slider 135 is rotated ina pitching direction indicated by an arrow 144 in a state in which thefirst pair of beams 131 and 132 and the second pair of beams 133 and 134are bent. At this time, a twist deformation occurs in the first pair ofbeams 131 and 132 of the gimbal 125, and a bend deformation occurs inthe second pair of beams 133 and 134.

As indicated by an arrow 145, the magnetic head slider 135 is rotated ina rolling direction also. At this time, bend deformations occur in thebeams 131 and 132 in the respective directions opposite to each other,and bend deformations occur in the beams 133 and 134 in the respectivedirections opposite to each other.

FIG. 25 shows a resonance mode of the first-order bend. A deformationoccurs in the elastic portion 123 formed at the root of the suspension121, and the first pair of beams 131 and 132 and the second pair ofbeams 133 and 134 are deformed in the same direction.

FIG. 26 shows a resonance mode of the first-order twist. A twistdeformation occurs in the elastic portion 123 formed at the root of thesuspension 121 in such a manner so the right and left portions of theelastic portion 123 have different heights. The beam located on theright side of the gimbal 125 is deformed so as to be formed into aconvex shape facing upwards. The beam located on the left side of thegimbal 125 is deformed so as to be shaped into a convex facingdownwards. When the lengths l₁ and l₂ are selected so that the length l₂is equal to three or four times the length l₁, the rotation stiffnessresponses of the slider in the pitching and rolling directions becomesufficiently soft and are almost the same as each other.

As shown in FIG. 23, a composite type magnetic head 148 and fourterminals 1100A, 1100B, 1100C and 1100D are provided in the magnetichead slider 135. The magnetic head 148 includes an MR head forreproduction and an interactive type head for recording, these headsbeing integrated with each other. The magnetic head 148 is located at arear end surface of the magnetic head slider 135 in a relative movementdirection 146 with respect to the magnetic disk 1222.

As shown in FIGS. 27 and 28, lead wires 115A, 115B, 115C and 115D areconnected to the terminals 1100A, 1100B, 1100C and 1100D, respectively.Each of the lead wires 115A through 115D has a diameter of, for example,30 μm. The lead wires 115A-115D are laid on the side opposite to theside on which the magnetic head slider 135 is mounted, and are attachedto a center portion 36 of the fixing portion 130 by means of an adhesive116, which can be an insulation adhesive or an insulator containing aninsulator. Further, the lead wires 115A-115D extend along thelongitudinal center line 137 of the suspension 121 towards the baseportion of the suspension 121, and are fixed thereto at two points bymeans of the adhesive 116.

Reference numbers 117 ⁻¹, 117 ⁻² and 117 ⁻³ respectively indicate afirst fixing point, a second fixing point and a third fixing point atwhich the lead wires 115A through 115D are fixed by means of theadhesive 116. The first fixing point 117 ⁻¹ moves in accordance withmovement of the magnetic head slider 135. Hence, it is unnecessary to beconcerned about the stiffness of portions of lead wires 115A through115D between the terminals 1100A-1100D and the first fixing point 117 ⁻¹and to provide additional lengths of the lead wires 115A-115D. In FIG.27, such additional lengths of the lead wires 115A-115D are notprovided. The distance between the first fixing point 117 ⁻¹ and thesecond fixing point 117 ⁻² is long, and the stiffness of the lead wires115A-115B between the fixing points 117 ⁻¹ and 117 ⁻² little affects therotation stiffness of the gimbal 125.

The magnetic head suspension unit 120 has the following features. First,the rotation stiffness of the gimbal 125 is considerably small becauseof the characteristics of the T-shaped beams. Second, the gimbal 125 issupported at the four points 140-143, and hence, the resonance frequencyof vibration of the gimbal 125 is high even when the second pair ofbeams 133 and 134 is long. Third, the end of the suspension 121 can beformed so that it has a small width W1, and hence the resonancefrequency of vibration of the suspension 121 is high. Fourth, the flyingstability of the magnetic head slider 135 is excellent due to the abovefirst, second and third features. The fifth feature of the mechanism 120is such that the first pair of beams 131 and 132 has a short length l₁and is formed in the same plane. Hence, the first pair of beams 131 and132 has a large strength with respect to force received in the contactstart/stop operation, and a shear failure does not easily occur in thebeams 131 and 132. The sixth feature of the mechanism 120 is such thatthe stiffness of the lead wires 115A-115D does not affect the rotationstiffness of the gimbal 125.

As has been described above, the gimbal 125 is formed so that a pair ofT-shaped beams (which form an H-shaped beam) is provided with respect tothe center of the gimbal 125, and hence a low rotation stiffness and ahigh resonance frequency are achieved. More specifically, the rotationstiffness of the mechanism 120 becomes one-third of that of theaforementioned IBM 3380 type head suspension unit, while the resonancefrequency of the mechanism 120 is as high as that of the IBM 3380 typehead suspension unit. As a result, it becomes possible to stably fly acompact slider having a low airbearing stiffness.

Tables 1 and 2 show characteristics of the head suspension unit 120according to the fourteenth embodiment of the present inventionsupporting a 2 mm-length slider, and the IBM 3380 type head suspensionunit supporting which a 3.2 mm-length slider.

TABLE 1 COMPARISON OF STIFFNESS (static characteristics by computersimulation) Stiffness 1st embodiment 3380 type pitch stiffness 1.5 grfcm/rad 9.4 grf cm/rad roll stiffness 1.5 grf cm/rad 5.1 grf cm/radup/down stiffness 0.55 grf/mm 2.4 grf/mm equivalent weight ratio 0.740.72

TABLE 2 COMPARISON OF RESONANCE FREQUENCY (dynamic characteristic bycomputer simulation) Stiffness 1st embodiment 3380 type 1st bend 2.1 kHz2.1 kHz 1st twist 2.3 kHz 2.6 kHz in-plane 8.5 kHz 5.7 kHz

In order to make the equivalent weight ratio ((supporting springequivalent weight)/(slider weight) of the fourteenth embodiment equal tothat of the IBM 3380 type mechanism, the total length of the suspensionunit is short (10 mm), which is approximately half of that of the IBM3380 type mechanism. Further, the thickness of the suspension 121 of thefourteenth embodiment is 25 μm, which is approximately one-third of thatof the IBM 3380 type mechanism.

Table 1 shows data obtained by computer simulation. More specifically,Table 1 shows the pitch stiffness and roll stiffness of the gimbal 125of the fourteenth embodiment, and the up/down stiffness of thesuspension 121 thereof. Further, Table 1 shows the pitch stiffness andthe roll stiffness of the gimbal of the IBM 3380 type mechanism, and theup/down stiffness of the suspension thereof. It can be seen from Table 1that the rotation stiffness equal to one-third of the gimbal of the IBM3380 type mechanism can be obtained by optimizing the width and lengthof the grooves in the gimbal 125.

Table 2 shows the resonance frequencies of the fourteenth embodiment andthe conventional IBM 3380 type mechanism obtained by a computersimulation. The resonance frequencies of the fourteenth embodiment aresimilar to those of the IBM 3380 type mechanism.

As will be seen from the above, the magnetic head suspension unitaccording to the fourteenth embodiment of the present invention has alow stiffness and a high resonance frequency.

A description will now be given of a fifteenth embodiment of the presentinvention. In the following description, parts that are the same asthose shown in FIG. 23 are given the same reference numbers.

FIG. 29 shows a magnetic head suspension unit 150 according to thefifteenth embodiment of the present invention. The mechanism 150includes a gimbal 151. The gimbal 151 is formed so that the gimbal 125shown in FIG. 23 is rotated about the center 136 by 90°. Two T-shapedbeams 152 and 153 are arranged in the longitudinal direction of thesuspension 121.

FIG. 30 shows a magnetic head suspension unit 160 having a gimbal 161according to a sixteenth embodiment of the present invention. The gimbal161 has the aforementioned first pair of beams 131 and 132, and a secondpair of beams 33A and 34A. The beam 133A and the beam 131 form an acuteangle α. Similarly, the beam 134A and the beam 132 form an acute angleequal to the acute angle α. With the above structure, it becomespossible to form, without increasing the width W1 of the suspension 121,the second pair of beams 133A and 134A so that the length 2×l_(2a)thereof is greater than the length 2×l₂ of the second pair of beams 133and 134 shown in FIG. 23. Further, it is possible to narrow the end ofthe suspension 121. Hence, the rotation stiffness of the gimbal 161 isless than that of the gimbal 125 shown in FIG. 123. Thus, the magnetichead slider 135 in the sixteenth embodiment can be more stably fliedthan that in the fourteenth embodiment shown in FIG. 23.

FIG. 31 shows a magnetic head suspension unit 170 having a gimbal 171according to a seventeenth embodiment of the present invention. Amagnetic head slider 135A of the mechanism 170 includes flanges 172 and173 formed on the respective sides of the slider 35A. A magnetic headslider fixing portion 130A of the gimbal 171 includes an opening 174having a size corresponding to the magnetic head slider 135A. Theopening 174 is of a rectangular shape defined by a rectangular frame176. As shown in FIG. 31, the magnetic head slider 135A engages theopening 174, and the flanges 172 and 173 are made to adhere to the frame176 by means of an insulation adhesive or an adhesive containing aninsulator. In this manner, the magnetic head slider 135A is fixed to themagnetic head slider fixing portion 130A.

As shown in FIG. 32, the center G of gravity of the magnetic head slider135A is substantially located on the surface of the suspension 121.Hence, in a seek operation, the magnetic head slider 135A is moved byexerting a force on the center G of gravity. Thus, an unnecessaryrotation force about the center G of gravity of the magnetic head slider135A does not occur, and the unbalance of the magnetic head slider 135Ais reduced. As a result, the magnetic head slider 135A can stably fly inthe seek operation.

Further, the height of the magnetic head assembly can be reduced. Hence,it is possible to laminate layers of the head at reduced intervals andto provide an increased number of disks per unit length. As a result, itis possible to increase the volume storage density of the magnetic diskdrive and hence the storage density.

FIG. 33 shows a magnetic head suspension unit 180 having a magnetic headslider 135B according to an eighteenth embodiment of the presentinvention. The magnetic head slider 135B has a flange 181 formed aroundthe circumference thereof. The magnetic head slider 135B engages theopening 174, and the flange 181 is adhered to the magnetic head sliderfixing portion 130A by means of an adhesive which can be an insulationadhesive or an adhesive containing an insulator. That is, the eighteenthembodiment of the present invention differs from the seventeenthembodiment thereof in that the whole circumference of the magnetic headslider 135B is made to adhere to the fixing portion 130A. Hence, theadhesive strength is increased and the reliability of the magnetic headsuspension unit is improved.

FIG. 34 shows a magnetic head suspension unit 190 according to anineteenth embodiment of the present invention. FIG. 35 shows a free endof a suspension of the magnetic head suspension unit 190. The mechanism190 is designed so that it does not have any influence of the stiffnessof lead wires, which affect flying of the slider having a low airbearingstiffness. For example, when, in the case where four lead wires areconnected between the slider and the suspension (see FIG. 27), each ofthe lead wires has a diameter of 30 μm and has an additional length(free length) of 1 mm, the rotation stiffness of the gimbal isapproximately five times that of the gimbal in which there is no leadwire. This degrades the flying stability of the slider.

The magnetic head suspension unit 190 has wiring patterns 191, 192, 193and 194, which are formed by patterning a copper thin film formed by,for example, plating by means of the photolithography technique. Thewiring patterns 191-194 extend on a central portion of the lower surfaceof the suspension 121 in the longitudinal direction. Each of the wiringpatterns 191-194 is approximately 5 μm thick and 50 μm wide. Thethickness and width of the wiring patterns depend on the resistance ofthe conductive pattern and the capacity of the suspension 121.

Terminals 195A-195D made of copper are formed on the base portion of thesuspension 121. Further, terminals 196A-196D are formed in a terminalarea 130 a of the magnetic head slider fixing portion 130 of the gimbal125. The tops of the terminals 195A-195D and 196A-196D are plated by,for example, Au. This plating contributes to preventing exposure ofcopper and improving the bonding performance. Ends of the wiringpatterns 191, 192, 193 and 194 are respectively connected to theterminals 195A, 195B, 195C and 195D. The other ends of the two wiringpatterns 191 and 192 extend along the beams 133A and 131, and areconnected to the terminals 196A and 196B, respectively. The other endsof the wiring patterns 193 and 194 extend along the beams 134A and 132and are connected to the terminals 196C and 196D, respectively.

As shown in FIG. 36, the wiring patterns 191, 192, 193 and 194 areelectrically insulated from the suspension 121 by means of an insulatingfilm 197, and are covered by a protection film 198. The insulating film197 and the protection film 198 are made of photosensitive polyimide andare grown to a thickness of approximately 5 μm. The insulating film 197and the protection film 198 are respectively patterned by thephotolithography technique. The thickness of the insulating film 197 isdetermined on the basis of a capacitance between the conductive pattern(made of Cu) and the suspension (made of stainless steel).

As will be described later, polyimide has heat-resistance enough for anannealing process. Since polyimide has photosensitivity, it can beeasily patterned. Further, the polyimide films 197 and 198 havecorrosion resistance, and excellent reliability.

It is likely that the terminals 195A-195D and 196A-196D are etchedbecause these terminals are not covered by the protection film 198. Inorder to prevent the terminals 195A-195D and 196A-196D from beingetched, the surfaces of these terminals are covered by an Au film (notshown) having a thickness of approximately 1 μm formed by plating orvapor deposition.

As shown in FIG. 37, the magnetic head slider 135 is made to adhere tothe fixing portion 130 by means of an adhesive which can be aninsulation adhesive or an adhesive containing an insulator. Theterminals 196A-196D are located at a right angle with respect toterminals 1100A-1100D of the magnetic head 148 formed on the end surfaceof the magnetic head slider 135, and are respectively connected to theterminals 1100A-1100D by means of Au balls 1101A-1101D. The Au balls1101A-1101D are formed by means of, for example, a gold ball bondingdevice. In order to facilitate bonding, the terminals 196A-196D andterminals 1100A-1100D are located as shown in FIG. 37. In order tofacilitate a crimp operation on the Au balls 1101A-1101D, the terminals1100A-1100D are long in the direction of the height of the magnetic headslider 135 and are located so that these terminals 1100A-1100D face theterminals 196A-196D in the state where the head slider 135 is fixed tothe fixing portion 130.

In addition to FIG. 37, FIGS. 55-59 illustrate an embodiment with abonding ball connection in more detail.

FIG. 55 is a structural diagram of a magnetic disk apparatus to whichanother embodiment of the present invention directed to bonding balls isadapted, FIG. 56 is a cross section of the structure in FIG. 55, FIG. 57is a front view of an actuator in FIG. 55, FIG. 58 is an explanatorydiagram of the seventeenth embodiment of this invention in FIG. 55, andFIG. 59 is a diagram for explaining how to connect the embodiment.

FIG. 55 illustrates a magnetic disk apparatus which allows a head tofloat onto a magnetic disk to execute magnetic recording.

Provided on a base 60-1 of the apparatus are a 3.5-in magnetic disk 5-1,which rotates around a spindle shaft 64-1, and a magnetic circuit 63-1.An actuator 4-1 is mounted rotatable around a rotary shaft 62-1.

A coil 41-1 is provided at the rear portion of this actuator 4-1, asshown in FIGS. 59, 56 and 57, and the coil 41-1 is located in themagnetic circuit 63-1.

As shown in FIG. 56, nine arms 3-1 are formed at the front portion ofthe actuator 4-1, each arm 3-1 is formed at the front portion of theactuator 4-1, and each arm 3-1 is provided with support plate(suspension) 7-1 which has a magnetic head core (core slider) 8-1provided at the distal end.

This actuator 4-1, together with the coil 41-1 and magnetic circuit63-1, form a linear actuator. When current flows through the coil 41-1,the actuator 4-1 rotates around the rotary shalt 62-1 to move themagnetic head core 8-1 for a seek operation in a direction perpendicularto the tracks of the magnetic disk 5-1 (radial direction).

In FIG. 58, “7-1” is a support plate (suspension) made of metal having aspring property, such as stainless. An insulating layer is coated on thesupport plate, and a pair of wiring patterns 71-1 and suspensionconnector terminals 72-1 are formed thereon by a copper pattern. Thesupport plate 7-1 has its one end fixed to the arm 3-1 by laser spotwelding or the like.

“8-1” is a magnetic head core (core slider) which has a pair of coreslider connector terminals 82-1 and a thin-film magnetic head 81-1provided on the sides.

When the magnetic head core 8-1 is mounted on the support plate 7-1, theconnector terminals 72-1 of the support plate 7-1 and the connectorterminals 82-1 of the magnetic head core 8-1 are fixed with thepositional relationship as shown in FIG. 58(B) and 59(A), and gold ballsW about 0.1 mm in diameter are made to contact both gold-platedconnector terminals 82-1 and 72-1 and are subjected to pressure bondingand ultrasonic bonding by a ball bonder, the connector terminals 82-1and 72-1 are electrically and mechanically connected via the gold ballsW due to intermetal bonding. In this example, the magnetic disk 5-1 islocated upward of the diagram.

When the support plate 7-1 is provided with the wiring patterns 71-1 andconnector terminals 72-1 while the magnetic head core 8-1 is providedwith the connector terminals 82-1, they can be connected by gold ballbonding. Therefor, even the minute magnetic head core 8 can easily beconnected, thus accomplishing the miniaturization of the magnetic headassembly.

Further, unlike lead wires, wiring is not necessary, so that difficultwiring at the minute suspension is unnecessary, further facilitating theassembling.

Furthermore, the number of components is reduced to make the assemblingeasier and accomplish a small magnetic head assembly.

FIG. 59(b) shows a modification of the seventeenth embodiment in which adummy terminal 83-1 is provided at the flow-in side of the magnetic headcore 8-1, and a dummy terminal 73-1 is provided on the wiring pattern71-1 of the support plate 7-1 accordingly. With gold balls W about 0.1mm in diameter in contact with both gold-plated connector terminals 83-1and 73-1, pressure bonding and ultrasonic bonding are performed by aball bonder, those connector terminals 83-1 and 73-1 are connectedtogether via the gold balls W due to intermetal bonding.

Accordingly, the magnetic head core 8-1 has both ends connected by thegold balls W to the support plate 7-1, so that adhesion of the magnetichead core 8-1 to the support plate 7-1 is unnecessary and the connectioncan be made by the ball bonding step alone, further facilitating theassembly.

Although the lead wires are connected to the arm side terminals (seeFIG. 58(A)) of the wiring patterns 71-1 of the support plate 7-1 beforeconnecting to the arm 3-1 in this example, this wiring is easy becausethe arm 3-1 is relatively large.

The wiring patterns 191-194 bypass holes 1102A, 1102B and 1102C, asshown in FIG. 34 and extend up to an area close to the head slider 135.The hole 1102 c is used to fix the suspension 121 to the arm 122 (notshown in FIG. 34). The holes 1102A, 110B and 1102C are sized such that atool can be inserted therein.

As shown in FIGS. 34 and 35, dummy patterns 1103A-1103D and 1104A-1104Dare provided so that these dummy patterns are symmetrical to thebypassing portions of the wiring patterns 191-194 with respect to theholes 1102A and 1102B. The insulating film 197 and the protection film198 are provided for the dummy patterns 1103A-1103D and 1104A-1104D inthe same manner as the wiring patterns 191-194. The dummy patterns1103A-1103D and 1104A-1104D are provided in order to balance themechanical stiffness of the suspension 121 in the direction of the widthof the suspension 121.

As shown in FIG. 35, the wiring patterns 191-194 are arranged so thatthese patterns form a loop. This loop functions as an antenna, whichreceives noise components contained in the head signals. As the size ofthe loop is increased, the degree of the noise components is increased.In order to reduce the size of the loop, the wiring patterns 191 and 192respectively connected to the terminals 196A and 196B are arrangedbetween the hole 1102A and the magnetic head slider 135, and all thewiring patterns 191-194 are gathered in the vicinity of the hole 1102A.In order to balance the stiffness in the direction of the width of thesuspension, the dummy patterns 1104A-1104D are formed. For the samereason as above, the dummy patterns 1103A-1103D are formed in thevicinity of the hole 1102B.

As shown in FIG. 35, auxiliary films 1106 and 1107 having a belt shapeare formed along the right and left ends of the suspension 121. Theauxiliary films 1106 and 1107 are provided in order to receive aclamping force generated when the suspension 121 is clamped in a bendingprocess which will be described later. Such a clamping force is alsoreceived by the wiring patterns 191-194. The clamping force isdistributed so that the clamping force is exerted on not only the wiringpatterns 191-194 but also the auxiliary films 1106 and 1107. Hence, itis possible to prevent the wiring patterns 191-194 from being damaged.

As shown in FIGS. 34 and 35, a convex dummy pattern 1108 is provided inorder to prevent an adhesive from flowing from the fixing portion 130when the slider 135 is fixed to the fixing portion 130 and to preventthe slider 135 from being tilted due to the thickness of the wiringpatterns. More particularly, the convex pattern 1108 is used to form agroove in which an insulation adhesive used to fix the slider 135 issaved between the pattern 1108 and the terminals 196A-196D. Further, theconvex pattern 1108 is designed to have the same height as the patternshaving the terminals 196A-196D. If the dummy pattern 1108 is not used,the slider 135 will be inclined with respect to the fixing portion 130due to the height of the terminals 194A-194D. This degrades the flyingstability of the heads. Further, the use of the convex dummy pattern1108 increases the height of the adhesive to thus improve the insulationperformance. The convex pattern 1108 can be formed by a cooper-platedthin film similar to the wiring patterns 191-194. The protection film198 covers the convex pattern 1108. The adhesive is provided on a steppart between the wiring patterns and the convex pattern 1108.

The suspension 121 is produced by a process shown in FIG. 38. First, apattern formation step 1110 is performed. More particularly,photosensitive polyimide is coated on a stainless plate. The insulatingfilm 197 is formed by the photolithography technique. A copper film isformed by the plating process, the vapor deposition process or the like,and is patterned into the wiring patterns 191-194 by thephotolithography technique. Thereafter, photosensitive polyimide iscoated and is patterned into the protection film 198 and the auxiliaryfilms 1106 and 1107 by the photolithography technique. Polyimide can becoated by a spin-coat process, and is patterned and etched. A thin film,such as a Cr film, can be formed in order to improve the adhesivenessbetween the insulating film and the Cu film and between the Cu film andthe protection film and to improve the reliability of the adhesion.

Next, an etching step 111 is performed in order to form the openings126-129 and the holes 1102A-1102C and the outward form of the suspensionin the stainless plate. FIG. 39 shows suspensions 1202 before punchingfor cutting off bridge portions (not shown) to provide pieces, so thatthe suspensions 1202 are formed in a stainless plate 1201 and arrangedin rows and columns.

Then, a bending step 1112 is performed by bending the respective ends ofeach of the suspensions 1202 formed in the stainless plate 1201, so thatribs 121 a are formed. The bending step 1112 can be performed by pressso that the suspensions 1202 are processed at the same time.

Finally, an annealing step 1113 is performed at a temperature ofapproximately 400° C., so that internal stress can be removed. Further,a slider adhering step and an Au bonding step can be automaticallycarried out before the suspensions 1202 are punched. Hence, it ispossible to automatically perform the production process shown in FIG.38 and reduce the number of steps and the cost thereof.

The suspension 121 can be produced without performing the annealing step1113. In this case, as is shown in FIG. 40, the pattern formation step1110 and the etching step 1111 are performed, and subsequently theslider adhering step and the Au bonding step are carried out.Thereafter, the bending step 1112 is carried out to form the ribs 121 a.

As shown in FIG. 41, when interactive type heads 148A and 148B forrecording and reproduction are used as magnetic heads, the magnetic headslider 135 has the aforementioned two terminals 1100A and 1100B. In thegimbal 125, the two wiring patterns 191A and 192A are provided so thatthese wiring patterns extend on only the beams 132 and 134A, while twodummy patterns 1210 and 1211 are provided so as to extend on the beam131 and 133A in order to balance the mechanical stiffness of thesuspension 121 in the direction of the width of the suspension 121.

The magnetic head suspension unit 190 has the following features.

First, since the wiring patterns 191-194 are formed on the suspension121, it is not necessary to provide tubes for passing the lead wiresthrough the suspension 121. Hence, it is possible to prevent unbalancedforce caused by the lead wires and tubes from being exerted on themagnetic head slider 135 and to stably fly the magnetic head slider 135.

Second, due to use of the dummy patterns 1103A-1103D and 1104A-1104D,the rotation stiffness of the suspension 121 does not have polarity.Hence, the magnetic head slider can fly stably.

Third, the crimp connection using the Au balls 1101A-1101D enablesautomatic assembly and non-wire bonding between head terminals andpattern terminals.

In the aforementioned embodiments of the present invention, the beamsmay be curved.

A description will now be given of a magnetic head suspension unitsuitable for a more compact magnetic disk drive according to a twelfthembodiment of the present invention.

FIG. 42 shows a back surface of a magnetic head suspension unit 1230according to the twelfth embodiment of the present invention. FIG. 43shows a 1.8-inch-type magnetic disk drive 1231 to which the magnetichead suspension unit 1230 is applied.

The magnetic disk drive 1231 has an enclosure 1232 having almost thesame dimensions as those of an IC memory card. In the enclosure 1232,provided are a magnetic disk 1233 having a diameter of 1.8 inches, andan actuator to which two sets of magnetic head suspension units areattached. The magnetic disk drive 1231 is more compact than the magneticdisk drive 1220 shown in FIG. 3.

A magnetic head slider 135C is made compact in accordance withlight-sizing of the magnetic disk drive 1231. More particularly,dimensions a×b of the magnetic head slider 135C are 0.8 mm×1.0 mm, andare approximately one-quarter the area of the magnetic head slider 135shown in FIG. 23. In order to stably fly the compact magnetic headslider 135C, it is necessary to considerably reduce the stiffnesswithout decreasing the resonance frequency, as compared with themagnetic head suspension unit 130.

A suspension 1235 shown in FIG. 42 is made of stainless, and has a baseportion fixed to an arm 1236 of the actuator 1234 (see FIG. 43). Thesuspension 1235 has a width W2 of approximately 2 mm, a length L ofapproximately 9 mm, and a thickness to of approximately 25 μm, and isapproximately a half of the volume of the suspension 121 shown in FIG.23. The suspension 1235 is diminished, and hence the resonance frequencyof bending which will be described later is high.

The suspension 1235 is a sheet-shaped piece, and a flat plate piece towhich a bending process has not been subjected. Hence, there is noproblem of a bending process error which degrades the flying stabilityof the magnetic head slider. The suspension 1235 includes a suspensionmain body 1237 and a gimbal 1238 located on the end side of thesuspension 1235. The gimbal 1238 has a substantially U-shaped opening(through hole) 1239 formed in the suspension 1235. The gimbal 1238includes a magnetic head slider fixing portion 1240, a first beam 1241,a second beam 1242, a third beam 1244, and a connecting portion 1243.

The magnetic head slider fixing portion 1240 has a size corresponding tothe magnetic head slider 135C. The first beam 1241 and the second beam1242 extend along respective longitudinal ends of the suspension 1235from the end thereof. The connecting portion 1243 extends in thedirection of the width of the suspension 1235, and connects the firstbeam 1241 and the second beam 1242 together. The third beam 1244 extendsfrom the connecting portion 1243 to the magnetic head slider fixingportion 1240 in the longitudinal direction of the suspension 1235. Themagnetic head slider fixing portion 1240 is connected to the main body1237 of the suspension 1235 via the third beam 1244, the connectingportion 1243 and the first and second beams 1241 and 1242. Hence, therotation stiffness of the suspension 1230 can be reduced to a smallvalue due to bending of the entire beams.

As shown in FIG. 42, holes 1245, 1246 and 1247 with which a tool isengaged, and a pair of slits 1248 and 1249 are formed in the main body1237 of the suspension 1235. Adjustment slits 1248 and 1249 are used toreduce the rotation stiffness of the suspension. The holes 1245, 1246and 1247 and the slits 1248 and 1249 are formed by etching. Theconnectors 195A-195D, 196A-196D and the wiring patterns 191-194 areformed symmetrically with respect to the longitudinal direction of thesuspension 1235. The magnetic head slider 135C is made to adhere to thefixing portion 1240, and the terminals 196A-196D and 1100A-1100D arerespectively connected to each other by means of Au balls, as in thecase shown in FIG. 37.

The structure shown in FIG. 42 does not use dummy patterns because thelength and the width of the suspension 1235 are less than those of thesuspension shown in FIG. 34 and the loop formed by the wiring patternsis smaller than that shown in FIG. 34. However, it is preferable toarrange the wiring patterns and provide the dummy patterns as shown inFIGS. 34 and 35 in order to reduce the noise from the heads.

As shown in FIGS. 44A and 44B, the free end of the arm 1236 is bent sothat a substantially V-shaped cross section of the arm 1236 is formed inwhich the “V” is inverted. The free end of the arm 1236 has an upwardslant portion 1236 a and a downward slant portion 1236 b declined at anangle θ with respect to the horizontal direction.

The magnetic disk drive 1231 uses two magnetic head suspension units1230 so that the single magnetic disk 1233 is sandwiched between themechanisms 1230. As shown in FIG. 45, the suspension 1235 causes themagnetic head slider 135C to come into contact with the magnetic disk1233 when the magnetic disk 1233 is not being rotated. At this time, themain body 1237 of the suspension 1235 is caused to be bent andelastically deformed. The elastic force stored in the main body 1237 ofthe suspension 1235 generates a load F1, which urges the magnetic headslider 35C towards the magnetic disk 1233.

Since the arm 1236 is bent in the form of the inverted “V”, a wide gap1250 can be formed between an end 1236 c of the arm 1236 and themagnetic disk 1233, as compared with a case indicated by a two-dotchained line in which the arm 1236 is simply bent downwards.

A description will now be given of a moment exerted on the magnetic headslider 135C by means of the suspension 1235 when the suspension isloaded on the disk. As shown in FIG. 46, the main body 1237 of thesuspension 1235 and the third beam 1244 are bent. Hence, a moment isexerted by a center 1251 of the magnetic head slider 35C. A moment M1directed counterclockwise is exerted by the suspension main body 1237and the first and second beams 1241 and 1242. A moment M2 directedclockwise is exerted on the third beam 1244. The dimensions of thesuspension 1235 are selected so that the moments M1 and M2 are balanced.For example, the suspension 1235 is 9 mm long, and the gimbal 1238 is2.5 mm long. Further, the length and width of the main body 1235 of thesuspension 1237 are 5.7 mm and 2 mm, respectively. With the abovestructure, it is possible to stably fly the magnetic head slider 135C.

A description will now be given, with reference to FIG. 42, of pitchingand rolling of the magnetic head slider 135C.

(1) Pitching

The magnetic head slider 135C is rotated in the pitching directionindicated by arrow 144 in such a manner that the first, second and thirdbeams 1241, 1242 and 1244 and the suspension main body 1237 are bent. Atthis time, all the beams 1241, 1242 and 1244 are bent so as to bedeformed in the form of arch shapes. The gimbal 1238 is bent and hencethe suspension main body 1237 is bent. Hence, the pitch stiffness can begreatly reduced.

(2) Rolling

The magnetic head slider 135C is rotated in the rolling directionindicated by arrow 145 in such a manner that the first and second beams1241 and 1242 are respectively bent in the opposite directions and thesuspension main body 1237 is twisted. At this time, the gimbal 1238 isbent and hence the suspension main body 1237 is bent. Hence, the rollingstiffness can be greatly reduced.

A description will now be given of the first-order bend and thefirst-order twist of the magnetic head suspension unit 1230 obtainedwhen the suspension is vibrated.

(1) First-order bend

The suspension 1235 is bent and deformed, as shown in FIG. 47. Morespecifically, the suspension main body 1237, and the first, second andthird beams 1241, 1242 and 1244 of the gimbal 1238 are bent as shown inFIG. 45. The overall suspension 1235 is formed flexibly, but theresonance frequency of the first-order bend is high, while the stiffnessis small.

(2) First-order twist

The suspension 1235 is twisted as shown in FIG. 48. The gimbal 1238 isdeformed and hence the suspension main body 1237 is deformed. Hence, theoverall suspension 1235 is flexibly formed, but the resonance frequencyof the first-order twist is high while the stiffness thereof is low.

Tables 3 and 4 show characteristics of the magnetic head supportmechanism 1230 according to the twelfth embodiment of the presentinvention and the magnetic head suspension unit 130 of the fourteenthembodiment thereof shown in FIG. 23.

TABLE 3 COMPARISON OF STIFFNESS (static characteristics by computersimulation) Stiffness 7th embodiment 1st embodiment pitch stiffness 0.44grf cm/rad 1.5 grf cm/rad roll stiffness 0.24 grf cm/rad 1.5 grf cm/radup/down stiffness 0.36 grf/mm 0.55 grf/mm equivalent weight ratio 0.760.74

TABLE 4 COMPARISON OF RESONANCE FREQUENCY (dynamic characteristics bycomputer simulation) Stiffness 7th embodiment 1st embodiment 1st bend1.6 kHz 2.1 kHz 1st twist 4.4 kHz 2.3 kHz in-plane 7.1 kHz 8.5 kHz

More particularly, Table 3 the pitch stiffness, the roll stiffness, andthe up/down stiffness of the suspension 1235 obtained by means of acomputer simulation. It can be from Table 3 that the pitch stiffness andthe roll stiffness of the twelfth embodiment of the present inventionare approximately one-quarter of those of the fourteenth embodimentthereof.

Table 4 shows the resonance frequencies of the fourteenth and twelfthembodiments of the present invention obtained by a computer simulation.It can be seen from Table 4 that the first-order bend resonancefrequency, the first-order twist resonance frequency and the lateralresonance frequency are kept very high.

It can be seen from Tables 3 and 4 that the magnetic head suspensionunit 1230 according to the twelfth embodiment of the present inventionhas a resonance frequency as high as that of the magnetic headsuspension unit 130 according to the fourteenth embodiment, andstiffness much less than that of the mechanism 130. Hence, the compactmagnetic head slider 135C can be stably flied.

In an alternative of the suspension, the base portion of the suspension1237 is bent, so that the suspension is supported in the same manner asshown in FIG. 23 and the load F1 shown in FIG. 45 is obtained. In thiscase, only portions 1255 and 1256 outside of the slits 1248 and 1249 arebent. Hence, unnecessary strain is not exerted on the wiring patterns191-194 located between the slits 1248 and 1249.

A first variation of the gimbal 1238 of the suspension 1235 will bedescribed. A gimbal 1238 ⁻¹ shown in FIG. 49 has a first beam 1244 ⁻¹having a long width A, and an opening 1239 ⁻¹ having a long length B.First and second beams 1241 ⁻¹ and 1242 ⁻¹ are long.

FIG. 50 shows a second variation 1238 ⁻² of the gimbal 1238. The gimbal1238 ⁻² has first and second beams 1241 ⁻² and 1242 ⁻² each having asmall width C.

FIG. 51 shows a third variation 1238 ⁻³ of the gimbal 1238. The gimbal1238 ⁻³ has first and second variations 1241 ⁻³ and 1242 ⁻³ having alarge width D.

FIG. 52 shows a fourth variation 1238 ⁻⁴ of the gimbal 1238. The gimbal1238 ⁻⁴ has a fourth beam 1260 connecting the center of the end of themagnetic head slider fixing portion 1240 and the suspension main body1237 together. The fourth beam 1260 functions to prevent a deformationof the magnetic head slider fixing portion 1240, but increases therotation stiffness. Hence, it is desired that the width of the fourthbeam 1260 be as small as possible and the length thereof are as long aspossible.

FIG. 53 shows a fifth variation 1238 ⁻⁵ of the gimbal 1238. The gimbal1238 ⁻⁵ has first and second arch-shaped beams 1241 ⁻⁵ and 1242 ⁻⁵.

As shown in FIG. 54, a bent connecting plate 1261 is fixed to an arm1236A, and the suspension 1235 is fixed to the connecting plate 1261.Hence, it is not necessary to subject the arm 1236A to bending stresses.

In the variations shown in FIG. 49 through 132, it can be said that thethird beam 1244 shown in FIG. 42 has the same width as the fixingportion 1240 and is integrated with the fixing portion 1240.

In the fourteenth through nineteenth embodiments, the load applied tothe magnetic head slider is generated by bending the spring portion ofthe suspension. Alternatively, it is possible to employ the arm fixingstructure used in the twelfth embodiment of the present invention inwhich the spring portion is kept flat.

The present invention is not limited to the specifically disclosedembodiments and variations, and other variations and modifications maybe made without departing from the scope of the present invention.

What is claimed is:
 1. A method for assembling a recording/reproducinghead assembly which comprises a slider and a slider supporting member,the slider having a head element and a head terminal connected to thehead element, the slider supporting member including a terminal to beconnected to the head terminal, and the head slider being fixed on theslider supporting member so that the head terminal faces the terminal ofthe slider supporting member, said method comprising the steps of:placing a conductive ball member in contact with both the head terminaland the terminal of the slider supporting member; and pressing the ballmember to bond the head terminal and the terminal of the slidersupporting member, whereby the ball member electrically and mechanicallyconnects both terminals.
 2. The method as claimed in claim 1, furthercomprising a step of plating both the terminals with gold beforecontacting the ball member.
 3. The method as claimed in claim 2 whereinthe ball is made of gold.
 4. The method as claimed in claim 3, furthercomprising a step of irradiating ultrasonic waves during the pressing ofthe ball member.
 5. The method as claimed in claim 1, further comprisingthe steps of forming said slider supporting member including the stepsof forming a suspension with a gimbal, and forming said terminals of theslider supporting member on said gimbal.
 6. The method as claimed inclaim 5, further including the step of integrally forming said gimbalwith said suspension.
 7. The method as claimed in claim 1, furtherincluding the step of forming at least one wiring line on said slidersupporting member and connecting said at least one wiring line to saidterminal of the slider supporting member.
 8. The method as claimed inclaim 7, further including the step of forming said slider supportingportion with a suspension, and forming said at least one wiring line bya wiring pattern on said suspension.
 9. The method as claimed in claim1, wherein both terminals face each other at a right angle.
 10. Themethod as claimed in claim 1, further comprising a step of irradiatingultrasonic waves during the pressing of the ball member.
 11. The methodas claimed in claim 1, wherein the ball member is made of gold.
 12. Amethod for assembling a recording/reproducing head assembly whichcomprises a slider and a slider supporting member, the slider having ahead element and four head terminals the slider supporting memberincluding four terminals, and the head slider being fixed upon theslider supporting member so that each head terminal faces one of theterminals of the slider supporting member such that four pairs ofcorresponding terminals are formed, said method comprising the steps of:forming a conductive ball member on each of said pairs of correspondingterminals so that said conductive ball touches both one of said headterminals and one of said terminals of the slider supporting member; andpressing the ball member to bond each head terminal with the terminal ofthe slider supporting member, whereby the ball member electrically andmechanically connects one of said head terminals with one of saidterminals of said slider supporting member.
 13. The method as claimed inclaim 12, further including the step of forming the slider supportingmember with a gimbal, and forming said four terminals of the slidersupporting member on said gimbal.
 14. The method as claimed in claim 13,further including the step of integrally forming said gimbal with saidsuspension.
 15. The method as claimed in claim 12, further including thestep of forming the slider supporting member with four wires, andconnecting one of said four wires to each terminal of the slidersupporting member.
 16. The method as claimed in claim 15, furtherincluding the step of forming the slider supporting member with asuspension having a wiring pattern, and forming said four wires by saidwiring pattern.